I have just uploaded a compiled version of the Postgres driver for aolserver 3.2+ad12. It should also work with other versions. See readme.txt for usage details.
Also note that I am not going to maintain this thing. I compiled it for my own tests and do not wish to persue this any further. Have fun with it, though :)
You can find it in file-storage: https://openacs.org/new-file-storage/one-file?file_id=109